<?php

/**
 * This is just a JSON helper copied from ibm.com
 * http://www.ibm.com/developerworks/xml/library/x-xml2jsonphp/
 *
 */


// Maximum Recursion Depth that we can allow.
define ("MAX_RECURSION_DEPTH_ALLOWED", 25);
// An empty string
define ("EMPTY_STR", "");
// SimpleXMLElement object property name for attributes
define ("SIMPLE_XML_ELEMENT_OBJECT_PROPERTY_FOR_ATTRIBUTES", "@attributes");
// SimpleXMLElement object name.
define ("SIMPLE_XML_ELEMENT_PHP_CLASS", "SimpleXMLElement");

class api_helpers_json {

    public static function xmlStringToJson($xmlStringContents) {
        $simpleXmlElementObject = simplexml_load_string($xmlStringContents);
    
        if ($simpleXmlElementObject == null) {
            return(EMPTY_STR);
        }
    
    
        $jsonOutput = EMPTY_STR; 
    
    
        // Let us convert the XML structure into PHP array structure.
        $array1 = self::convertSimpleXmlElementObjectIntoArray($simpleXmlElementObject);
    
    
        if (($array1 != null) && (sizeof($array1) > 0)) { 
            // Create a new instance of Services_JSON
            // Let us now convert it to JSON formatted data.
            $jsonOutput = json_encode($array1);
        } // End of if (($array1 != null) && (sizeof($array1) > 0))
    
    
        return($jsonOutput); 
    } // End of function transformXmlStringToJson
        
    
    
    public static function convertSimpleXmlElementObjectIntoArray($simpleXmlElementObject,
    &$recursionDepth=0) { 
      // Keep an eye on how deeply we are involved in recursion.
    
    
      if ($recursionDepth > MAX_RECURSION_DEPTH_ALLOWED) {
        // Fatal error. Exit now.
        return(null);
      }
    
    
      if ($recursionDepth == 0) {
        if (get_class($simpleXmlElementObject) != SIMPLE_XML_ELEMENT_PHP_CLASS) {
          // If the external caller doesn't call this function initially 
          // with a SimpleXMLElement object, return now. 
          return(null); 
        } else {
          // Store the original SimpleXmlElementObject sent by the caller.
          // We will need it at the very end when we return from here for good.
          $callerProvidedSimpleXmlElementObject = $simpleXmlElementObject;
        }
      } // End of if ($recursionDepth == 0) { 
    
    
      if (get_class($simpleXmlElementObject) == SIMPLE_XML_ELEMENT_PHP_CLASS) {
        // Get a copy of the simpleXmlElementObject
        $copyOfsimpleXmlElementObject = $simpleXmlElementObject;
        // Get the object variables in the SimpleXmlElement object for us to iterate.
        $simpleXmlElementObject = get_object_vars($simpleXmlElementObject);
      }
    
    
      // It needs to be an array of object variables.
      if (is_array($simpleXmlElementObject)) {
        // Initialize the result array.
        $resultArray = array();
        // Is the input array size 0? Then, we reached the rare CDATA text if any.
        if (count($simpleXmlElementObject) <= 0) {
          // Let us return the lonely CDATA. It could even be
          // an empty element or just filled with whitespaces.
          return (trim(strval($copyOfsimpleXmlElementObject)));
        }
    
    
        // Let us walk through the child elements now.
        foreach($simpleXmlElementObject as $key=>$value) {
          // When this block of code is commented, XML attributes will be
          // added to the result array.
          // Uncomment the following block of code if XML attributes are 
          // NOT required to be returned as part of the result array. 
          /*
    if((is_string($key)) && ($key == SIMPLE_XML_ELEMENT_OBJECT_PROPERTY_FOR_ATTRIBUTES)) {
            continue;
          }
          */
    
    
          // Let us recursively process the current element we just visited.
          // Increase the recursion depth by one.
          $recursionDepth++; 
          $resultArray[$key] = 
            self::convertSimpleXmlElementObjectIntoArray($value, $recursionDepth);
    
    
          // Decrease the recursion depth by one.
          $recursionDepth--;
        } // End of foreach($simpleXmlElementObject as $key=>$value) { 
    
    
        if ($recursionDepth == 0) {
          // That is it. We are heading to the exit now.
          // Set the XML root element name as the root [top-level] key of
          // the associative array that we are going to return to the caller of this
          // recursive function.
          $tempArray = $resultArray;
          $resultArray = array();
          $resultArray[$callerProvidedSimpleXmlElementObject->getName()] = $tempArray;
        }
    
    
        return ($resultArray);
      } else {
        // We are now looking at either the XML attribute text or
        // the text between the XML tags.
        return (trim(strval($simpleXmlElementObject)));
      } // End of else
    } // End of function convertSimpleXmlElementObjectIntoArray.
}